In the prior art there are several forms of electrical jacks that have been adapted for side-by-side mounting in an electrical jack panel. An example is shown in U.S. Pat. No. 3,822,415. More recent electrical jack units are illustrated in U.S. Pat. Nos. 4,073,463 granted Feb. 14, 1978 to James R. Bailey et al. and 4,368,941 granted Jan. 18, 1983 to Ronald G. Martin. The Martin U.S. Pat. No. 4,368,941 illustrates a jack frame that is formed of a single cast material similar to that shown in FIG. 1 of this application. To assist in understanding the present invention it is helpful to understand some of the details of the prior art unit.
The prior art electrical jack unit is identified with the numeral 10 having an integral cast frame 12 with a sleeve section 14 and a support beam section 15. The support beam section 15 includes a single support beam 16 that extends outward at a right angle to the sleeve section 14.
The sleeve section 14 includes an output monitor sleeve member 18, an output sleeve member 20 and an input sleeve member 22 that extend outward from a forward surface of the sleeve section for receiving cylindrical jack plugs. The sleeve section 14 has mounting holes 24 at the ends thereof for mounting the electrical jack unit in parallel side-by-side relationship with other jack units in an electrical jack panel.
The prior art electrical jack unit 10 includes three jack spring switch assemblies that are identified as a monitor output jack spring switch assembly 26, an output jack spring switch assembly 28 and an input jack spring switch assembly 30. Each of the switch assemblies 26, 27 and 30 correspond with respective sleeve members 18, 20 and 22. The switch assemblies 26, 28 and 30 are secured to the support beam 16 by bolts 32 that extend through the switch assemblies and the support beam 16.
Although the electrical jack unit 10 illustrated in FIG. 1 was a substantial improvement in the technology, it still possessed significant weaknesses. Although the cast frame 12 is quite rigid it does permit the spring assemblies 26, 28 and 30 to twist with respect to the support beam 16 in a lateral direction enabling the switch contacts to engage adjacent switch contacts of adjacent units, causing electrical shorting. Furthermore the insertion of cylindrical jack plugs into their respective sleeve members 18, 20 and 22 caused substantial moment forces to be produced with respect to the bolts 32 minimizing the pressure that can be applied to the physical switch contacts. Furthermore over time the switch assemblies become loose and are rendered ineffective.
One of the principal objects of this invention is to provide a much improved electrical jack unit that overcomes many of the disadvantages of the prior art electrical jack units, particularly with respect to the electrical jack unit 10 illustrated in FIG. 1. The advantages of this invention will become apparent upon reading the following detailed description of a preferred embodiment.